C3 Q&A: A Conversation with Douglas H. Thamm, V.M.D, DACVIM

Doug Thamm is a physician-scientist, learning about cancer through his experiences treating and studying patients. Only, his patients happen to have four legs. Here we speak with Thamm about the unique opportunities of veterinary medicine and how his own cancer diagnosis 25 years ago influenced his career.

C3: We understand you took a year off from vet school to treat Non- Hodgkins lymphoma. Can you tell us how your own cancer experience guided your career?

Thamm: The really interesting thing about my cancer is that when I was in vet school, veterinary oncology wasn’t what it is today. It wasn’t something that had crossed my mind as a specialty. I’d done a lot of research as an undergrad and knew I wanted a career that had a component of research – then after my personal experience of cancer, I kind of said, “Hey I wonder what’s going on with canine oncology?” It was kind of like the little spark that made me check it out.

C3: And since then has veterinary oncology caught up with human oncology?

Thamm: Actually, it some ways it’s ahead of human oncology! One thing about having fewer vets treating cancer is there just aren’t enough of us to specialize. There aren’t veterinary breast or sarcoma or hem-onc specialists. We sort of have to be Jacks of all trades, treating and studying a wide variety of cancers. Sometimes that lets us see the forest for the trees – see the big picture, when maybe some human oncologists only see things within their subspecialty.

C3: Such as?

Thamm: Well, I’d argue that we may have been a little ahead in the approach of defining a cancer by its molecular driver rather than its microscopic appearance – because we see many cancer types, we’re positioned to see patterns between types, for example, instead of calling a tumor “breast” or “lung” cancer, we might see it as ALK-positive or EGFR-positive cancer, defining the cancer by the genetic changes that created it.

C3: Does that mean there are actually advantages to studying cancer in dogs compared to studying the disease in humans?

Doug Thamm, VMD, DACVIM

Thamm: Sure, there are a couple advantages. For example, human clinical trials generally can test new drugs only after everything else has failed. Because there’s no accepted standard of care in veterinary medicine, we can study new treatments much earlier in the course of care. And because a lot of what we do routinely requires sedation, we have the opportunity to biopsy over and over again, getting little pieces of tumor tissue each time that can tell us things like how the cancer in changing in response to therapy or whether a drug is doing what it’s supposed to be doing in the tumor tissue. And there’s much more flexibility in combination therapies – we can put a new drug in with chemotherapy, radiation therapy or surgery; in contexts where it has the chance to be much more effective. That couldn’t be done so quickly and easily in humans.

C3: We’ve been talking about the difference between veterinary and human oncology, but do you also see places where the fields are converging?

Thamm: I think one of the things, that has very recently come to the fore is the era of immunotherapy – and dogs have immune systems that are exactly like human immune systems. Tumors show up in dogs and have learned to avoid the immune system just like humans. In contrast, mouse tumors usually don’t evolve in the same way to avoid the immune system. Researchers are trying to do all these crazy things with mice when there’s a huge population of dogs walking around, a third of whom are going to get cancer and may benefit from these immunotherapies.

C3: So we help dogs and learn something, too?

Thamm: Our goal as veterinarians is, first and foremost, to improve the health and welfare of animals, but we have the potential to go
one better. We have the opportunity to answer questions that could translate into better therapies for humans as well.